Self-loading or “automatic” pistols use an extractor to remove a spent casing (during operation) or live round from the chamber of the pistol. The extractor is mounted on the breech block, which may be part of the slide for pistols such as the Model 1911 which have a slide. The extractor has a hook that engages a groove in the base of the cartridge. Engagement between the hook and cartridge extracts the cartridge (or spent casing) when the breech block separates from the breech, either during operation or when the slide is “racked”, or moved from battery to open position.
The “bar” dimension, the distance between the extractor hook and an opposite wall of the breech block, is important to ensure reliable operation of a self-loading pistol. If the bar dimension is too small, then stripping and chambering of a round during operation is inhibited. If the bar dimension is too large, then extraction of the spent casing is erratic. As is typical of machined parts comprising a mechanism, the dimensions of the parts will vary within an acceptable tolerance band. Dimensional tolerances on the extractor and the slide/breech block will combine (add or subtract) and affect the bar dimension. For some pistols, such as the Model 1911, the tolerance on the bar dimension is relatively small. To meet this tolerance, it is found advantageous to fit the extractor to the slide/breech block.
Fitting the extractor is a time consuming process whereby the armorer must assemble the extractor onto the slide/breech block, measure the bar dimension, and then adjust the size of the extractor by removing material from the extractor if the bar dimension is too large. This is done by a “cut and try” method, and requires considerable skill to effect efficiently, as several attempts may be required. Removal of material must be done with care, least the extractor dimension become too small, thereby rendering it useless. There is clearly a need for an extractor, and a method of fitting an extractor to a slide/breech block, which improves the efficiency of the process.